Traffic signal



May 26, I925. 1,538,952

A. w. RAM

TRAFFIC SIGNAL Filed June 29, 1921 5 Shets-Sheet 1 May 26 1925. 1,538,952

A. W. RAM

TRAFFIC SIGNAL Filed June 29, 1921 I 5 Sheets-Sheet 3 May 26 1925.

A. W. RAM

TRAFFIC SIGNAL Filed June 29, 1921 5 Sheets-Sheet 4 'l l l l l l l 'l l l lll l May 26, 1925.

TRAFFIC S IGNAL Filed June 29, 1921 5 Sheets-Sheet 5 flbbowuy Patented May 26, 1925.

UNITED STATES PATENT OFFICE.

ALFRED W. RAM. OF WASHINGTON. DISTRICT OF COLUMBIA, ASSIGNOR T WILLIAM H. FINCKEL, JR, TRUSTEE, OF WASHINGTON, DISTRICT OF COLUMBIA.

TRAFFIC SIGNAL. 7

Application filed .Tune 29, 1921. Serial No. 481,314.

To all whom. it may ('o'nccmi:

lie it known that I, ALFRED \V. RAM, a citizen of the United States, residing at \Vashington, in the District of Columbia, have invented a certain new and usefullmprovement in Traflic Signals, of which the l'ollowing is a full, clear, and exact description.

The object of this invention is to proride a signaling device adapted primarily for regulating vehicular trafiic on city streets, but ada 'itable also to the regulation of the traiiic of road vehicles at the intersection of roadways with railways; I5 and the invention contemplates such a device as will allow a certain predetermined number of vehicles to pass in one direction before any vehicles are allowed to pass in an intersecting direction, but capable of passing single vehicles alternately in both such directions when no more than one such vehicle approaches from either direction at a time.

To this end, the invention consists in a trafiic signal adapted to be located at the intersection of lines of vehicular trafiic, such signal being operatively connected with devices located in the line of vehicular traffic and adapted to be actuated by vehicles, IW whereby when a vehicle approaches said intersection and actuates one of said devices, said signal will be operated to present to the driver of such vehicle a signal that he may proceed, presenting at the same time to the drivers of vehicles approaching from a direct-ion intersecting that travelled by said first-mentioned vehicle, a signal to stop; and the invention consists further in means whereby the signal and devices may be so modified as to adapt the invention to use in connection with roadways intersecting railways, all as I will proceed now to explain and finally claim.

In the accompanying drawings illustratinc the invention, in the several figures of which like parts are similarly designated, Figure 1 shows in perspective the general arrangement of the signal and devices of my invention at a street crossing. Fig. 2 59 is a sectional elevation showing one of the device's actuated by a vehicle for operating the signal. Fig. 3 is a view showing a portion of the mechanism shown in Fig. 2 so modified as to adapt the device for use in connection with railways. Fig. 4 is'a sectional elevation showing on a larger scale the mechanism operated by the device shown in F g. 2. Fig. 5 is a sectional elevation showing the mechanism for accomplishing the readjustment of the mechanism shown in Fig. 4 after the passage of a vehicle. Fig. 6 IS a sectional elevation showing the signal proper and its connected operating devices. Fig. 7 is a section taken on the hne 7-7 of Fig. Fig. 8 is a View similar to Fig. 7 but showing an arrangement of the parts sultable when the invention is used in connection with railways. Fig. 9 is a wiring diagram illustrating the electrical connections of the various mechanisms when the device is designed for use at the intersection of roadways. Fig. 10 is a wiring -d1agram showing the electrical connections of the device when adapted for use in connection with railways. Fig. 11 shows a modified form of the device actuated by vehicles.

Referring more particularly to the drawings, it will be seen that I provide a signal member indicated generally by the numeral 1 comprising a base member 2, adapted to be suitably secured to the roadway as by a plate 3 cooperating with a flange 4 upon a casing 5 embedded in the roadway. The base 2 is provided with a bearing member 6 through which passes a revoluble standard 7 carrying at its upper end a suitable sign 8 which may be illuminated, if desired, having four arms bearing the legends or signals Go and Stop, as is customary with ordinary trafiic signals. As the means of illuminating the sign forms no part of this invention, it will suffice to say that the arms may be of box-like construction as shown, and provided with transparent or other plates 9 bearing the above-mentioned signals, those bearing the signal Go being preferably colored green with white lettering and those bearing the signal Stop being colored red with white lettering, as is the common practice, and each arm having within it electric or other illuminating means.

'W'ithin the casing 5 is mounted a pair of solenoids or like electromagnets 10 and 11, provided with a slidable core 12 connected by means of a lever 13 and pin 14 with the standard 7, this core 12 being adapted to. be held fixedly so that the signal will remain in either Go or Stop position Ill) against extraneous influences, such as wind 17 electrically connected with both of the solenoids 10 and 11 by a part winding from each so as to operate to withdraw the detent 15 from the recess 16 upon the energizing of either solenoid 10 or 11. lhe detent is held normally in engagement withthe notch by means of a spring 18. Movement of the standard from Go to Stop position and vice versa is limited by a pin 19 cooperating with a slot 20 in the bearing member 6.

Located in the roadway, at such a distance from the street intersection as would allow a vehicle travelling at an ordinary rate of speed to stop before reaching such intersection, is a device comprising a pair of plates 21 and 22 (see Fig. 2), the plate adapted to be first contacted with by the wheels of an approaching vehicle having a l blunt edge 23 for a purpose hereinafter appearing, and both of the plates being hingedly connected to a rod 24 mounted in a well 25 and having its lower end pivotally connected as at 26 with a plunger 27 work ing in a socket 28 and pressed normally upwardly by a spring 29 of such tension as to be depressed only by vehicles as heavy'or heavier than a motorcycle. This rod 24 is provided with a lug 30 adapted to normally rest upon a projection 31 formed upon the side of the casing of the well 25 so that the I rod may be moved downwardly only by a vehicle so approaching as to first contact with the plate 21 and by engagement of the wheels of said vehicle with the blunt edge 23 of said plate push it forward so as to release the lug 30 from the projection 31. Immediately upon the passage of the vehicle entirely over the plates 21 and 22, the spring 29 will return the rod 24 to its upper position and the lug 30 will be forced to engage the projection 31 by means of a pivoted link 32 connected with the rod and with the side of the casing tending to force the rod toward said projection as it is raised by the spring 29. By this arrangement, it will be seen that any vehicle approaching the device so as to strike the plate 22 first, will not operate the rod 24 because it will beheld in a raised position by means of the lug and projection.

Mounted adjacent the well 25 is a casing 33 containing mechanism for establishing an electric circuit through the solenoids of the signal, this mechanism including a shaft 34 mounted in hearings in the casing and extending through one side thereof and having mounted upon this extension a ratchet wheel 35 bearing aplurality, in this case eight, pins 36, with which cooperates a pusher 37 provided with a tooth 38. The ratchet wheel has a number of teeth 39 equal in number to the number of pins 36 and these teeth are engaged successively by a pawl 40. By means of this mechanism it will be seen that as the vehicle passes over the'plates 21 and 22 in proper operating direction, the rod 24 will be depressed and moved forward twice, once as the front wheels pass over, and once as the rear wheels pass over, and at each movement of this rod, the pusher 37 will rotate the ratchet wheel 35 through a distance equal to the-space of one tooth and impart a similar movement to the shaft 34.

Within the casing 33 and mounted upon the shaft 34 is a cam 41 having onl one high surface 42 adapted to successive y engage a pluralit of push rods 43 slidably mounted in gui es 44 and having notches 45 cooperating with spring pressed pins 46 whereby the rods are held in either depressed or raised position. Each push rod 43 carries a pair of spring contacts 47-;cooperating with stationary contacts 48 carried by insulating blocks 49 mounted upon the casing, these stationary contacts being electrically connected with one of the solenoids 10 or 11 as the case may be, as will be later described. Carried by the guides 44 is a pair of electro-magnets 50 so arranged that when energized they will attract keepers 51 mounted on the push rods 43 to return said push rods to retracted or depressed position and open the circuit through the solenoid.

By this arrangement, it will be seen that when a vehicle operates this mechanism, the cam will be turned to the position shown in Fig. 4, when the front wheels of the vehicle depress the rod 24, thus establishing a circuit through the solenoid of the signal, and when the rear wheels of the vehicle depress the rod 24, the cam will be turned out of engagement with the push rod and to a position intermediate the push rod just operated and that next in order, the push rod just operated being held in raised position to maintain the electrical circuit through the solenoid of the signal by means of its notches 45 cooperating with the pins 46.

At a position in the streetclosely adjacent the intersection is a second device similar in every respect to that shown in Fig. 2, but instead of being connected for operating the mechanism shown in Fig. 4, is arranged to operate the mechanism shown in Fig. 5, which comprises a casing 52 provided with a shaft 53, similar to the shaft 34, and extending through one side of the casing and carrying a ratchet wheelsimilar to the ratchet wheel 35. Within the casing 52 and upon the shaft 53 is mounted a cam 54 having one high point 55 adapted to cooperate in order with a plurality of'contact makers 5t. comprising pivoted arms bearing contacts 57 adapted to makecontact with terminals 58 to which are connected wires leading to the electromagnets '50. These arms are normally held depressed by springs 59 which force them against :sto s 60.

By the use of this evice, it will be seen that when the vehicle has passed over the plates 21 and 22, which operate the mech-- anism in the casing 33 and has raised the push rods 43 .to establish a circuit through the solenoid of the signal, and has thentravelled through the intervening space of the roadway between that device and'the similar device operating the mechanism in the casing 52, last described, and has operated this mechanism, the front wheels of the vehicle will have turned the cam 54 to the position shown in Fig. 5, and will have established an electrical circuit through the electroma nets and retracted the push rod 43 to its depressed position by attracting the keeper 51, thus breaking the circuit through the solenoid of the signal. The rear wheels will then turn the cam 54 so as to permit disengagement of the contacts 57 from the terminals 58 and thereby break the circuit through the electromagnets 50.

When in the apparatus as illustrated, four vehicles pass over the device controlling the mechanism contained in the casing 52, the rear wheels of the last vehicle of the four. to pass over the device will move the high point of the cam 54 into position to 0peratc and pass by the circuit breaker 61, which. as will be later described, controls the whole circuit for the solenoid of the signal on that particular portion of the roadway, thereby making it i1npossible.until another vehicle has passed over the device controlling the mechanism in casing 33, for the signal to be moved to the Go position for that portion of the roadway, and giving vehicles approaching in the intersecting direction right of way.

Referring now to the wiring diagram shown in Fig. 9. the operation of the electrical devices of the invention is substantially as follows :The diagram illustrates a signal and the controlling devices therefor :t'or one angle only of a pair of intersecting streets, the other angle thereof comprising merely a duplication of the devices shown with the exception of the signal proper and its solenoids. A$uming that a vehicle approaches the intersection from the direction indicated the arrow A, Fig. 1, the front wheels of this vehicle will depress the plates and operate the device in the casing 33, which we will call the circuit establishing mechanism, to energize the solenoid 62 through the contacts 47 and 48, wires 63, 64, circuit breaker 61 and wire 65, at the same time energizing solenoid 17 to actuate the detent 16, to release and move the signal so that the word Go thereof will be presented to the driver of the vehicle. However, should another vehicle have entered the street indicated byethe arrow B, the solenoi'd 66 will have en energized in the same manner through the wires 67, 68 and I 69, and as the pul of each solenoid u on its core is the same, the solenoid 66 havlng been first energized and having the greater v portion of the core within it and subject to its influence, will maintain the signal in.

such position that it will show the signal Sto tothe vehicle entering atA and Go to the'vehicle entering at B.

Assuming now that no vehicles are a proaching in the direction ofthe arrow l3 and that thevehicleapproaching in the direction of the arrowA hasturnedthe signal so that it reads Go for vehicles approaching in that direction, and that three other vehicles are following it in that direction, these three vehicles will successively operate the push rods 43 so that all of them are in contact making position. Then, as these four vehicles passover the devices controlling the mechanism mounted in the easing 52, which We will call the circuit interrupting mechanism, they will successivelyenergize all of the pairs of electromagnets 50- and return all of the push rods depressed position, thereby breaking the circuit, the rear wheels of the fourth vehicle causing the cam 54 to operate the circuit breaker 61. as above described, thereby breaking the entire circuit for the solenoid 62 momentarily and allowing vehicles a chance to pass in the direction of arrow B. It will thus be seen that after four, vehicles have passed in one direction, other vehicles coming in that direction will have the signal Stop confronting them if vehicles approaching in the'direction of the arrow 13 have operated the solenoid 66. for the reason 4 thatimmediately the solenoid 62 is de-energized by the breaking of its circuit through circuit breaker 61, the solenoid 66, which has been energized, will draw the core. into it and thereby rotate the signal.

Obviously, therefore, the traflic signal, in the case shown, will operate automatically to allow one or more vehicles up to four to pass in one direction before vehicles are al lowed to pass in the other direction, or vehicles may pass alternately ineach direction, so long as there is no vehicle waiting in the space between the circuit establishing and circuit interrupting mechanisms of the street of the intersecting direction.

In adapting the invention for use with roadways intersecting railways, it is desirable to have the signal setv normally at Sto for vehiclesa iii-cachin on the holding the signal in Stop position or for immediately returning it to Stop position after it has been turned to Go position by a vehicle in, the roadway.

A further change in the mechanism is that inasmuch as there is no need for allowing a number of vehicles to pass over the railroad tracks at a time, the railroad trains having the right of way at all times, only one circuit establishing contact and only one circuit interrupting contact for the one circult establishing contact is necessary. Therefore, instead of having the ratchet wheel 35 for the circuit establishing mechanism, I need have only a lever 71 which will oscillate in unison with the oscillation of the rod 24 through a link 72 to move the high point 42 of the cam 41 into and out of engagement with the push rod 43. A similar connection of lever and link with the cam 54 of the circuit interrupting mechanism will be substituted for the ratchet wheel of that mechanism.

In the diagram, (Fig. 10) 73 indicates the rails of the railway, 74 the solenoids of the road signals energized by the trains, 75 the solenoids energized by vehicles on the roadway, 76 the circuit establishing mechanism, 77 the circuit interrupting mechanism, and C and D block signals.

7 As above stated, the road signals are normally set to present the signal Stop to drivers of vehicles on the roadway, so that when a train enters the portion of the rails 73 controlling the solenoids 74 these solenoids will be energized and the signals will therefore remain in the Stop position and cannot be changed by vehicles approaching on the roadway because of this previous energizing of the solenoids 74 whose action is augmented by springs 70 and cannot be overcome by energizing solenoids 7 However, if there is no train travelling in either direction on that portion of the railway controlling solenoids 74, a vehicle approaching on the roadway will operate the solenoid-controlling mechanism to energize the solenoids 7 5 and will overcome the springs 70 and shift the signals to Go. Of course, the section of the rails 73 controlling the solenoids 74 will be of such extent in both directions from the roadway as to make passage of road vehicles over the tracks safe should a train enter the section as a vehicle is crossing the tracks.

The two signals are connected in parallel so that both will operate simultaneously.

train, and a block signal D arranged at the point where the train ceases to affect my signal. Therefore block signals C will be set and unset simultaneously with my signal, and block signals D 'will be set when thetrain ceases to afi'ect my signal and will be unset when the train leaves the block. By this arrangement the same source of electricity used for operating the block signals may be used for operating my signals if desired.

While the invention is shown and described in what I now consider to be its preferred form, it is conceivable that various changes may be found advisable in later developments. For example, the lates 21 and 22 instead of reaching entire y across the roadway, as shown. may extend only part way across from the right-hand side, especially those actuating the circuit interrupting mechanism, and in such an installation it will not be essential that the device be provided with means for preventing its actuation by vehicles travelling in the direction opposite to the direction of those by which it is intended to be actuated. To meet this condition, I have devised the mechanism shown in Fig. 11, which comprises a rod 78 to which the plates 21 and 22 are connected, the plate 21 like 22 having a beveled ground contacting edge instead of the blunt edge 23. This rod 78 is mounted to slide vertically in a casing 79, provided at its lower end with a chamber 80 in which is mounted a spring 81 hearing against a seat 82 on the end of rod 78 and adapted to hold the rod normally in full upwardly projected position as determined by the stop 83. Pivotally connected to the rod 78 is a hook member 84 which extends through an opening in the casing 79 and is so arranged with relation to the ratchet wheel 85 of the circuit establishing or circuit interrupting mechanism as to successively engage pins 86 thereon. This hook member 84 is held normally in engagement with the pins'86 by a spring 87. The pawl 88 prevents backward rotation of the mechanism. The distance between the pins on the ratchet and the full downward movement of the rod 78 is so proportioned that each downward movement of the rod will, through the hook member 84, advance the ratchet wheel through an arc of forty-five degrees. as is the case in the embodiment of the device previously described.

What I claim is 1. In a trailic signal, the combination with intersecting traflic lanes, of signal means for controlling traflic across the intersection, and vehicle actuated means for controlling said signal means, whereby not more than a predeterminednumber of vehicles may ass in one direction before the signal means is actuated to signal approach of vehicles in an intersecting direction.

2. In atrafiic signal, the combination with ated switch mechanism for deenergizing intersecting traflie lanes, of signal means for said operating mechanism, whereby not controlling trafiic across the intersection, more than-a predetermined number of vehi- -mined number of vehicles and thereby per- -more than a predetermined number of ve hicles may pass in one-direction before tlte intersecting trafiic lanes, of signal means for and means arranged in the traflic lanes and cles may pass in one direction before the responsive to the movement of vehicles for signal means is actuated to signal approach controlling said signal means, whereby not of vehicles in anintersecting direction.

7. In a traflic'signal, the combination with signal means is actuated to signal approach controlling traflic across the intersection inof vehicles in an intersecting direction. eluding an electrically controlled operating 3Q'In a traflic signal, signal means located mechanism, switch mechanism for energizadjacent to the intersection of lines of traflic, ing said operating mechanism, switch mechvehicle actuted means for imparting move-\anism for deenergizing said operating mechment to said signal means to signal approach anism, and means including vehicle actuof trafiie in one direction and to permit pasated, devices for actuating said switch mech sage.of a'predeterinined number of vehicles anisms, whereby not more than a predeterin that direction, and including means for mined number of vehicles may pass in one rendering said first mentioned means modirection before the signal means is actuated 'mentarily incapable of actuatincg said sigto signal approach of vehicles in an interpredetersccting direct-ion.

8. In a traific signal, the combination with mitting actuation of the signal means to sigintersecting traific lanes, of signal means for nal approach of vehicles in an intersecting controlling trafiic across the intersection indirection. eluding electrically actuated operating mech- 4. In a traflie signal, signal means located anism, a source of electrical energy, connecadjacent to the intersection of lines of traftions between said source and said operating fie, means associated with said signal means mechanism, and vehicle actuated switch for imparting movement thereto, means for mechanism for energizing and deenergizing energizing said movement-imparting means, said operating mechanism interposed in the means for interrupting the influence of said connections between said operating means energizing means, vehicle actuated means and the source of electrical energy, whereby operatively connected with said energizing not more than a predetermined number of means, and vehicle actuated means operavehicles may passin one direction before the tively connected with said interrupting signal means is actuated to signal approach means, the two said vehicle actuated means of vehicles in an intersecting direction. being spaced apart a distance suflicient to 9. In a trafiic signal, the combination with accommodate a predetermined number of interseetingtraific lanes, of signal means for vehicles, and connections between the enercontrolling trafiic across the intersection ingizing means and the interrupting means eluding electrically controlled operating whereby said signal means having been means, means including vehicle actuated moved by the actuation by a vehicle of said circuit establishing means and vehicle actuenergizing means is incapable of returning ated circuit interrupting means for controlto its initial position until the actuation of ling said operating means whereby not more nal means after passage of sai theinterrupting means by all vehicles conthan a predetermined number of vehicles tained in the space between the two vehicle may pass in one direction before the signal actuated means. means is actuated to signal approach of ve- 5. In a traffic signal, the combination with hicles in an intersecting direction, said cirintersecting tratlic lanes, of signal means for euit establishing and circuit interrupting controlling trafiic across the intersection inmeans including switch members equal in cluding an electrically controlled operating number to the predetermined number of vemeehanism, and means including vehicle hicles. actuated switch mechanism for energizing 10. In a tra'liic signal, the combination and deencrgizing said operating mechanism, withintersecting traffic lanes, of signal whereby not more than a predetermined means for controlling traffic across the inter number of vehicles may pass in one direction section including electrically controlled operbefore the signal means is actuated to sigating means, means including vehicle actunal approach of vehicles in an intersecting ated circuit establishing means and vehicle direction. actuated circuit interrupting means for con- 6. In a trafiic signal, the combination with trolling said operating means whereby not intersecting traffic lanes, of signal means for more than a predetermined number of vehicontrolling trafiic across the intersection incles may pass in one direction before the eluding an electrically controlled opera-ting signal means is actuated to signal approach mechanism, and means including vehicle of vehicles in an intersecting direction, said actuated switch mechanism for energizing circuit establishing and circuit interrupting said operating mechanism and vehicle actumeans including switch members equal in number to the predetermined number of vehicles. and said circuit interrupting means including a circuit breaker for rendering temporarily inoperative all of the switches of said circuit establishing means.

11. In a traflic signal, the combination with intersecting trafiic lanes, of signal means for controlling trafiic across the intersection, means responsive to electrical energy for imparting signalling motion to the signalling means, means for actuating said motion-imparting means including a plurality of circuit establishing mechanisms, one of which is located in each traflic lane and arranged for actuation by vehicles to establish a circuit through said motion imparting means, and a plurality of similarly located circuit interrupting mechanisms arranged for similar operation subsequently to the operation of the circuit establishing mechanisms to interrupt the circuit through the motion imparting means, whereby not more than a predetermined number of vehicles may pass in one direction before the signal means is actuated to signal approach of vehicles in an intersccting direction.

12. In a traflic signal, the combination with intersecting trafiic lanes, of signal means for controlling trailic at the intersection, means for imparting si nalling motion to said signal means including a pair of solenoids the cores of which are connected. to said signal means, one of said solenoids operating to move the signal means in one direction and the other solenoid operating to move the signal in the opposite direction, and means including a circuit establishing mechanism located in each traiiic lane at each side of said intersection, means operable by passage of a vehicle for actuating said circuit establishing mechanism to close a circuit through one of said solenoids to impart signalling motion tosaid signal means in one direction, and'similarly located circuit interrupting mechanism provided with vehicle operated actuating means for opening the circuit through the energized solenoid to thereby permit the previously closed circuit through the other of said solenoids to impart signalling motion to said member in the opposite direction, whereby not more than a predetermined number of vehicles may pass in one direction before the signal Ineans is actuated to signal a proach of veholes in an intersecting direction.

13, In a 'trafiic si a1, a signal member, a solenoid for operating said member, means for establishing a circuit through said solenoid including a lurality of contact devices, means for operating said contact devices successively including a vehicle actuated member, and vehicle actuated means for inter-v rupting the circuits so established including a plurality of electromagnets adapted to move said contact devices out of circuit establishing position and means for establishing a circuit through said electromagnets.

14. In a trafiic signal, a signal member, means connecting said member with a pair of solenoids whereby said member is actuated to signal the approach of trafiic travelling in one direction and the stoppage of tratfic travelling in an intersecting direction and vice versa, means for establishing a circuit through one of said solenoids including a plurality of contact devices capable of malntaining the circuit through one of said solenoids, vehicle actuated means for operating said contact devices successively during the passage of a number of vehicles whereby one of said solenoids will hold said signal set during such passage of vehicles equal in number to the number of contact devices, a plurality of circuit interrupters, vehicle actuated means for operating said interrupters successively to interrupt the circuits estab lished by said contact devices, and a circuit breaker for breaking the circuit of all the aforesaid contact devices and permit actuation of the signal member due to the operation of a similar set of contact devices for establishing a circuit through the other of said solenoids to signal approach of tralfic travelling in the intersecting direction.

In testimony whereof I have hereunto set my hand this 28th day of June, A. D. 1921.

ALFRED IV. RAM. Witnesses:

W. H. Fmonnn, J r., HARRY O. JARBOE. 

